The delivery of medications by injection may be in the form of a single administration(s), or a series of administrations that occur at predetermined intervals over a set time period. Medication can be delivered using a pump to a cannula that is placed into the target bone or tissue. Pumps for delivering the medication may be, for example, in the form of a syringe or a primary drug container, that is actuated to deliver a predetermined volume of medicine at set times or time intervals, or in response to a delivery trigger.
A number of injectable medication delivery applications require the placement of the delivery cannula remotely from the pump. In such applications, the delivery cannula may be fluidly coupled to the pump by flexible tubing, which allows for required placement of the cannula, convenient placement of the pump, and provides flexibility to the clinician to manipulating the medication delivery setup. For example, the pump may be supported on the surface of a table or in a bag, or on the patient's body itself.
Accurate placement of the cannula requires not only accurate placement for insertion, but also precise depth insertion. In this regard, it is desirable that there be minimum interference with the line of sight to the patient end of the cannula so the medical personnel may clearly visualize the penetrating end of the cannula along with the target tissue or bone. Ensuring delivery of medication at the correct depth is critical to maximizing efficacy of many medications and compliance with indicated route of administration. For example, too deep of penetration of a cannula may result in intramuscular delivery as opposed to an intended subcutaneous delivery, while too shallow penetration may result in subcutaneous delivery, as opposed to an intended intramuscular delivery.